You dedication to avoiding the most minor of plot holes is commendable. Even though most games have very stretchy time, I commend you for sticking to accurate time measurement.
But if that is the limitation then why is there a problem? You have magical cowgirls taking magical pills to give them a magical fake pregnancy. And you think it is too far fetched to have a real pregnancy instead?
maybe the cowgirls, being a magical race, very rapidly grow the body of the infant causing them to swell up and look very pregnant. but then need to nurture it's soul for a year or two before giving birth.
maybe the magical pills, instead of causing a fake pregnancy, are only taken after already pregnant to accelerate a real pregnancy. Perhaps with limitations. such as not being safe to take after certain development milestone and having diminishing returns. So the first days of pregnancy are vastly accelerated, then it slows down, then they stop taking the pill. end result is that 15 to 30 days after the start of pregnancy you have cowgirl who is effectively 5 months pregnant and will from now on develop at a normal and natural pace